The primary efficacy endpoint is the change from baseline to Day 56 in the 17-item Hamilton DepressionRating Scale (HAM-D) total score

The main secondary endpoints are the changes from baseline to Day 56 in the HAM-D depressed mood item, Montgomery-Asberg DepressionRating Scale (MADRS) total, and Clinical Global Impression (CGI) Severity of Illness scores.

The primary outcome measure used is the MADRS (Montgomery-Asberg DepressionRating Scale). At study end response criteria is defined as a 50% reduction in total MADRS score and remission defined as less or equal to 10.